U.S. patent number 4,629,164 [Application Number 06/463,892] was granted by the patent office on 1986-12-16 for container with memory.
This patent grant is currently assigned to Imperial Chemical Industries, PLC. Invention is credited to John A. Sommerville.
United States Patent |
4,629,164 |
Sommerville |
* December 16, 1986 |
Container with memory
Abstract
A container having associated with it at least one memory device
in which a record of the contents of the container is stored, the
memory device being addressable such that the record of contents
may be altered during use of the container to maintain a record of
the remaining contents of the container.
Inventors: |
Sommerville; John A.
(Cirencester, GB2) |
Assignee: |
Imperial Chemical Industries,
PLC (London, GB2)
|
[*] Notice: |
The portion of the term of this patent
subsequent to August 28, 2001 has been disclaimed. |
Family
ID: |
10528145 |
Appl.
No.: |
06/463,892 |
Filed: |
February 4, 1983 |
Foreign Application Priority Data
Current U.S.
Class: |
239/69; 222/23;
239/302; 239/71; 239/690 |
Current CPC
Class: |
B05B
7/2486 (20130101); A01M 7/0092 (20130101); B05B
9/06 (20130101); B05B 3/18 (20130101); B05B
5/16 (20130101) |
Current International
Class: |
A01M
7/00 (20060101); B05B 3/18 (20060101); B05B
3/00 (20060101); B05B 5/00 (20060101); B05B
9/04 (20060101); B05B 5/16 (20060101); B05B
9/06 (20060101); B05B 7/24 (20060101); A01G
027/00 () |
Field of
Search: |
;239/8,690,708,71,302,69
;364/509,510,500,502 ;222/223,23,30 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kashnikow; Andres
Assistant Examiner: Malpede; Scott
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
We claim:
1. A container comprising:
a body for holding material to be dispensed, and
at least one electrically-addressable memory device in which a
record of the contents of said container is stored,
said record including electrically-alterable data defining the
quantity of material held in said body, and
said memory being arranged to be addressed during dispensing of
said material to effect alteration of said data to maintain in said
record an updated definition of the quantity of said material
remaining in said body.
2. A container as claimed in claim 1 in further combination with a
system coupled to said container including a microprocessor which
is arranged to control distribution of said material and which is
responsive to the quantity dispensed from said container and
including means for altering said record of the contents in
dependence on the volume of said material dispensed from the
container.
3. A container as claimed in claim 1 further comprising mechanical
and electrical connection means connected to said memory device and
adapted to be removably connected electrically, mechanically and
fluidically to a system which distributes said material held in
said body.
4. A container as claimed in claim 1 in which said memory device,
when altered, is irreversibly altered.
5. A container as claimed in claim 4 in which said memory device
comprises a plurality of fusible links and in which said record of
the contents of the remaining material in said container is
maintained by successively fusing ones of said plurality of fusible
links.
6. A container as claimed in claim 2 in which said memory device is
preset with a security code which prohibits unauthorised containers
being connected to said system.
7. A container as claimed in claim 2 in which said memory device is
preset with the identity of the contents of the container, said
identity being stored as a digitally formatted predetermined
series.
8. A container as claimed in claim 2 in which said system which
distributes the contents is a spraying system and includes means
for electrostatically charging the spray produced by a spray head
and in which said spraying system is designed to be vehicle
mounted, said microprocessor being powered by the vehicle's
electrical supply and being responsive to inputs from the
operational variables of said vehicle and having means to control
the dispensing of contents from said container.
9. A container as claimed in claim 1 in which said memory device is
attached to a closure forming part of said container.
10. A container comprising:
a body for holding material to be dispensed;
at least one electrically-addressable memory device in which a
record of the contents of said container is stored;
said record including electrically-alterable data defining a
quantity of material held in said body;
said memory being arranged to be addressed during dispensing of
said material to effect alteration of said data to maintain in said
record a definition of said quantity of material remaining in said
body;
a system coupled to said container including a microprocessor which
is arranged to control distribution of said material and which is
responsive to the quantity dispensed from said container and
including means for altering said record of the contents in
dependence on the volume of said material dispensed from the
container;
said memory device being preset with the identity of the contents
of the container, said identity being stored as a digitally
formatted predetermined series; and
said memory device being additionally preset with information
relating to the incompatibility of the contents of the container
with other chemical substances, said information represented in
said predetermined series and said microporcessor having means for
prohibiting the mixing of incompatible chemicals.
11. A non-reusable fluid container comprising:
a body portion for holding a predetermined quantity of fluid to be
dispensed in a predetermined application and thereafter not
intended for further such usage;
a closure portion fluidically closing said body portion except for
a predetermined fluid passageway;
an electrically-addressable and permanently electrically alterable
memory device integrally associated with the container;
said memory device being initially set to record data representing
said predetermined quantity and to provide electrical data signals
representing same when suitably addressed;
said memory device being permanently electrically alterable by
addressable input electrical signals to irreversibly change said
recorded data so as to represent only a reduced quantity of stored
fluid; and
connection means for removably connecting said container including
said fluid passageway and said memory device, mechanically,
electrically and fluidically to a using system adapted to perform
said predetermined dispensing application and to maintain an
irreversible permanent record in said memory device of the quantity
of fluid remaining in said container.
12. A non-reusable fluid container as in claim 11 wherein said
memory device comprises a programmable read only memory (PROM)
integrated circuit chip.
Description
The present invention relates to containers and more particularly
to containers with a memory which stores information relating to
the contents of the container.
This application is related to earlier filed copending commonly
assigned application Ser. No. 348,087 filed. Feb. 11, 1982 (now
U.S. Pat. No. 4,467,961) and to the following copending commonly
assigned applications also filed concurrently herewith on Feb. 4,
1983:
Ser. No. 463,938 now U.S. Pat. No. 4,533,702
Ser. No. 463,939 (now abandoned in favor of U.S. Pat. No.
463,941)
Ser. No. 463,940 (now abandoned in favor of U.S. Pat. No.
463,941)
Ser. No. 463,941
Ser. No. 463,942 (now abandoned in favor of U.S. Pat. No.
463,938)
Ser. No. 463,943 (now abandoned in favor of U.S. Pat. No.
463,938)
Ser. No. 463,952
Ser. No. 463,893 refiled as Ser. No. 766,674
All of the above-listed applications name different inventive
entities but were developed as part of a joint development
effort.
Containers of this type are particularly useful in the field of
agricultural chemicals e.g. pesticides and/or herbicides and the
memory is particularly useful in assisting the application of the
chemical when the container is connected into a distribution system
such as a vehicle mounted spraying system. The chemical will
normally be in a liquid form but it is possible in other
applications that it is in a powder form.
Previously known containers have included preset resistors which
can for example identify one or more parameters relating to the
chemical in the container such as for example a standard rate of
application. Such resistor systems are however limited in the
amount of information that they can provide.
It is an object of the present invention to provide a container
suitable for use with a vehicle mounted spraying system, the
container including a memory device in which information relating
to the chemical in the container is stored and in which the
contents of the memory are alterable during operation of the
spraying system to reflect the usage of the chemical in the
container.
The present invention therefore provides a container having
associated with it at least one memory device in which a record of
the contents of the container memory is stored, said memory device
being addressable such that the record of contents may be altered
during use of the container to maintain a record of the remaining
contents of the container.
The present invention will be described in conjunction with a
tractor driven spraying system in which the spraying is controlled
by microprocessors. The spraying system controls the spraying rate
by monitoring tractor speed, air temperature etc and also by
reference to standard spraying rates identified within the
container memory which may be amended by hand controls operable by
the driver. Additionally since it may be required to spray two or
more chemicals at the same time the memory contains information
relating to the incompatibility of the chemical in the container
with other chemicals. These other chemicals are contained in
similar containers with memories and the microprocessor can either
compare the identity of the two chemicals and check them against a
list contained in its own memory or it can compare information on
incompatibility obtained from each container memory.
Since each container has associated with it a memory containing
information relating to the identity of the chemical in that
container it is vital that the containers are not readily
refillable by inexperienced personnel. To this end the memory is
responsive to the use of the chemical in the container to record
the usage of the chemical preferably in an irreversible manner for
example by blowing fusible links in an electronically programmable
read only memory (EPROM). In this way as say each one tenth of the
contents is used a link can be blown and when the tenth fuse has
been blown the container will be empty. If the container is
illegally refilled the microprocessor will read the EPROM and
decide that the container is empty, even though it is full, and
will shut down the spraying system. Thus refilling of containers
with toxic chemicals which are either harmful or in the wrong
concentrations for the particular system is avoided.
Although the present invention is described with reference to a
tractor driven spraying system, for which it has particular
relevance it may be used in containers for other purposes such as
for example paint spraying where a mixture of paints is required at
specified percentage rates or in a large computer controlled
industrial chemical complex where the addition of some ingredient
chemicals must be carefully controlled.
Embodiments of the invention will now be described in relation to a
tractor mounted spraying system with reference to the accompanying
drawings, in which
FIG. 1 is a schematic diagram of a first type of a spraying system
showing a prior art container;
FIG. 2 is a vertical section through a spray nozzle shown in FIG.
1;
FIG. 3 is a schematic diagram of a second type of spraying system
showing a prior art container,
FIG. 4 shows diagrammatically a sprayhead malfunction detector
circuit which may form a part of the systems of FIGS. 1 and 3;
FIG. 5 shows diagrammatically a second type of sprayhead
malfunction detector circuit;
FIG. 6 is a diagonal rear perspective view of a tractor mounted
spraying system incorporating a container according to the present
invention;
FIG. 6A is a more detailed perspective view of the interconnections
between the various modules of the embodiment shown in FIG. 6;
FIG. 7 is a schematic diagram of the architecture of the electronic
hardware within the system of FIG. 6;
FIG. 7A is a more detailed schematic diagram of the architecture of
the electronic components of the system shown in FIG. 7;
FIG. 8 shows the fluid circuit of the embodiment of FIG. 6
incorporating a plurality of containers according to the present
invention;
FIG. 9 is a vertical section through a container according to the
present invention;
FIG. 10 is a top view of the tractor cab unit shown in FIG. 6;
FIG. 11 is a side sectional view through an electro-hydraulic
connector useful in the system of FIG. 6;
FIG. 12 is a front view of the socket face of the connector of FIG.
11;
FIG. 13 is a vertical section through a valved hydraulic connector
useful in the system of FIG. 6;
FIG. 14 is a front view of the socket half of another type of
electrical connector useful in the system of FIG. 6;
FIG. 15 is a front view of the corresponding plug half of the
connector of FIG. 14;
FIG. 16 is a section through the socket half of FIG. 14, in a plane
parallel to the face;
FIG. 17 is a vertical section through a spray nozzle used in the
system of FIG. 6; and
FIGS. 18-20 comprise flow charts for exemplary programs to be used
in conjunction with the spray control unit microprocessor shown in
FIG. 7; and
FIG. 21 is a flow chart for an exemplary program to be used in
conjunction with the display unit microprocessor shown in FIG.
7.
The system of FIG. 1 is mounted on a tractor (not shown). It
comprises a demountable container 10 (e.g. of about 25 liters
capacity). A male screw-thread coupling 11 of the neck of the
container 10 cooperates to give a liquid-tight seal with
corresponding female screw-thread coupling 12 carried on the
tractor and forming part of the liquid distribution system 13.
Liquid delivery system 13 leads from coupling 12 via an
electrically operated metering pump 14 to a spray boom 15 carrying
a number of nozzles 16. The construction of these is shown in more
detail in FIG. 2. Each nozzle is surrounded by an annular electrode
26 (65 in FIG. 2) which is earthed. The body of each nozzle is made
of electrically-conducting plastic, and is electrically connected
via leads 17 to a junction-box 18, which communicates via
high-tension lead 19 with one high voltage output terminal 21 of
high-voltage generator 20. Generator 20 is powered from the 12-volt
tractor battery 22 via the container 10.
FIG. 2 is a detail, in vertical section, of a typical electrostatic
sprayhead used in the invention. It comprises a nozzle 60 having a
liquid outlet or mouth 64 in the form of an annular gap between an
outer hollow cylinder 61 formed from conductive plastics and an
inner solid cylinder 62 formed from conductive plastics. Around
nozzle 60, and behind the mouth 64, an annular electrode 65 of bare
metal is symmetrically disposed.
The positive pole of the tractor battery 22 is connected, via
switch 23, to a contact 24 carried on the tractor. This abuts a
contact 25 on the container, which connects via a variable
resistance 26 to a contact 27 on the container abutting a contact
28 carried on the tractor. Contact 28 is connected via lead 29 to
an input terminal of generator 20. by a similar arrangement, high
impedance pump 14 is powered from battery 22 via container 10. Lead
30 conveys current from battery 22 via switch 23 to a contact 31
carried on the tractor. This abuts a contact 32 on the container,
which connects via a variable resistance 36 to a contact 33 on the
container which, in turn, abuts a contact 34 on the tractor. Lead
35 connects contact 34 to pump 14.
In operation, the container 10 is supplied from the manufacturer,
having been filled with a suitable organic liquid (pesticide or
herbicide) formulation and sealed under safe factory conditions. At
the factory the variable resistances 26 and 36 are adjusted to
values suitable to the liquid in the container. This is
conveniently carried out in a way which prevents the customer from
subsequently changing the setting; e.g. the resistances 26 and 36
may be adjustable only from inside the container. At the site where
spraying is to be carried out, the container 10 is mounted on the
tractor, unsealed and coupled to the liquid delivery system 13 via
couplings 11 and 12, ensuring that the four sets of contacts 24,
25; 27, 28; 31, 32; 33, 34 are in electrical contact. It will be
appreciated that the contacts and the pre-set electrical control
apparatus 26, 36 may be located at any convenient location on
container, 10 and may comprise an electrical plug and socket
assembly. The tractor is then driven past the crops it is desired
to spray, and the switch 23 closed. This activates the pump 14 and
the generator 20, the output of both being controlled to the
desired degree by control of the voltage and/or current supplied to
each, which is a function of the setting of resistances 26 and 36.
spray is conveyed to nozzles 16 by the action of pump 14, where the
spray is charged by direct contact at the potential delivered by
generator 20. Spray leaving the nozzles 16 breaks up into
electrically charged droplets under the action of the electrostatic
field between nozzles 16 and earthed electrodes 26, and is
attracted to the plants or earth to be treated.
In the system described above with reference to FIG. 1, the
contents of container 10 are sprayed without further dilution. FIG.
3 shows a tractor-mounted system in which dilution takes place;
this however is carried out automatically, without the need for any
manual mixing and consequent risk of errors or accidents.
The system of FIG. 3 comprises a reservoir 155 for a diluent (e.g.
diesel fuel) for delivering diluent via a tap 156 to a mechanical
pump 17 driven by the tractor power take-off. Two containers 158,
159 of generally similar type to that shown in FIG. 1 contain
concentrated organic liquid pesticide formulations and are
connected via couplings 160, 161 to metering pumps 164, 165 which
serve to inject pesticide into the diluent stream at 166, 167. From
here the diluted formulation passes to a boom 168 carrying
electrostatic sprayheads 169 of the same type as shown in FIG. 1.
The sprayheads 169 are connected to one high-voltage terminal of a
high-voltage generator 170, powered by the tractor battery 171. No
provision for varying the output voltage of generator 170 is
illustrated, though such may readily be provided if required.
Metering pumps 164, 165 are also powered from battery 171 via
variable resistances 172, 173 mounted on containers 158 and 159, in
the same way as battery 22 powers pump 14 in FIG. 1. In operation,
the rate at which pesticide or herbicide from containers 158, 159
is provided to pumps 164, 165 is controlled by the voltage and/or
current which, in turn, is controlled by the setting of resistances
172, 173, without the need to make up special formulatins. To spray
two different incompatible pesticides, the flows from containers
158 and 159 may be directed to separate sprayheads.
Systems such as that shown in FIG. 3, containing a separate source
of diluent, may conveniently be made to flush pesticide out of the
nozzles and liquid delivery system, using pure diluent. The system
is thereby cleaned for re-use with different pesticides. Such
flushing may be made automatic.
In our invention, it is not necessary that flow through the liquid
delivery system be determined uniquely by the pre-set control
mechanism 172, 173 carried on the container. It is possible, for
example, for the pre-set control to determine a base value for the
flow rate, corresponding to a standard vehicle forward speed. Means
may then be supplied to sense the actual forward speed of the spray
vehicle and vary the flow from this standard as necessary so as to
compensate for variations from the standard forward speed, in such
a way that the amount of pesticide delivered per unit area remains
constant over a range of forward speeds. Speed may be sensed by the
rotation rate of a vehicle wheel, or by doppler sound or radar
measurements. It is also possible to provide means for the spray
operator to vary the standard flow rate, e.g. in exceptional
circumstances. For example, a crop heavily infested with pests may
be usefully sprayed at 150% or 200% of the normal rate; and a
lightly infested one at 50% or 75% of the normal rate.
Apparatus may also be provided to detect malfunctioning of the
electrostatic sprayheads used in the invention. One such possible
means is shown schematically in FIG. 4. In the lead 100 conveying
high potential from generator 99 to a particular sprayhead 101, a
high resistance 102 (say 1 megohm) is inserted. Means 103 are
provided for sensing the potential drop across this resistance.
Using a voltage of about 20 KV, and a liquid charging current of
about 2 micro amperes per nozzle, the potential drop across
resistance 102 will be about 2 volts. If sprayhead 101 becomes
wholly or partially blocked, the current will stop or reduce and
the voltage will drop correspondingly. If there is a short circuit,
e.g. between sprayhead 101 and earthed electrode 104, current and
voltage will increase. Accordingly a control circuit 105 is
provided to compare the potential drop sensed by means 103 with
standard satisfactory limits, and if these are exceeded circuit 105
lights a warning light 106 in the tractor driver's cab. This tells
the driver that one sprayhead is not operating correctly (and which
it is). In a typical prior art spraying system, sprayhead blockages
may go undetected for substantial periods, and lead to crop loss
through failure to apply correct rates of pesticide.
A second possible means for detecting malfunctioning is shown in
FIG. 5. A probe 110 adjacent a sprayhead nozzle 111 has a charge
induced on it which depends on the charge on the liquid leaving the
nozzle 111. This charge is sensed by a field-effect (high input
impedance) transistor 112. A circuit 113 is provided to compare the
charge sensed by the transistor 112 against an appropriate range of
standard values, and, if the range is exceeded, to light a warning
light 114 in the tractor-driver's cab. Here a nozzle blockage will
reduce the charge induced on probe 110, as will any reduction in
the voltage supplied to nozzle 111.
If desired, signals from detector means of the type shown in FIG. 4
or FIG. 5 (or both) may be combined, and used to vary the flow
through the delivery system until the combined or individual
signals are within pre-set limits. Alternatively or additionally,
such variations may be used to vary the voltage from the high
potential system until the combined or individual signals are
within pre-set limits.
In the prior art system shown in FIGS. 1 to 5 the preset resistors
in container 10 provide only limited information to a control
system. The spraying system shown in FIGS. 6 to 21 includes a more
complicated control system and the container according to the
present invention is described with reference to its use in such a
complex control system.
Referring first to FIGS. 6 and 7, a tractor 200 has mounted on it a
modular spraying system 201 comprising a cab or display unit 202, a
radar unit 203 a trailer or spray control unit 204 and a spray boom
205. The trailer unit 24 and the cab unit 202 each contain
respective control microprocessors 206, 207 which communicate with
each other via a simple serial data link comprising lines 208, 218.
The trailer unit 204 further carries demountable containers 209,
210 containing pre-formulated spray chemical and a demountable
container 211 containing flushing diluent. Fluid from the
containers 209, 210 and 211 may be made to pass through fluid
circuit 212 (described in more detail in connection with FIG. 8
below) of electrostatic spraying heads or nozzles 213 mounted on
the boom 205.
The radar speed monitor allows automatic compensation for
variations in forward speed to maintain accurate chemical dosage.
As shown, this is an add-on unit to the tractor but it is
anticipated that built-in radars will become increasingly standard
in future tractors.
Each container carries a memory circuit (preferably an integrated
microcircuit) coding device 214 which is pre-coded with information
and which electrically communicates with trailer microprocessor 206
via data links 215. Microprocessor 206 also communicates with
liquid detectors 216 which feed its information via data links 219
and with electrical valves 221 and pumps 228 to which it sends
instructions via data links 222, 220, respectively. Microprocessor
206 also sends instructions to nozzles 213 via data link 227
(typically a simple serial "daisy-chain" type of link). Of course,
as will be appreciated, each data link contained wholly or mostly
within the environment of the trailer unit housing the CPU 206,
containers, liquid pumps, liqud sensors, valves, etc. (e.g. 215,
219, 222 and 220) may actually comprise many separate conductors
directed to/from respective ones of the various container coded
memory circuits, liquid detectors, valves, metering pumps, etc. The
data link which extends therebeyond, (e.g. to the nozzles and boom
sections and/or to the cab unit are preferably simple series two
wire digital links to minimize the complexity of cabling and
connectors necessary to complete the system in the hostile
environment of heat, light, humidity, vibration, etc.
Microprocessor 206 is also preferably provided with an internal
timer. The cab unit 202 comprises, as well as microprocessor
circuits 207, a panel 223 (see FIG. 10) having controls 224 by
means of which the tractor driver gives instructions to
microprocessor 207 and displays 225 by which the microprocessor 207
passes information to the tractor driver. The radar unit 203 feeds
information about tractor speed to the microprocessor 207 via data
link 226. Electrical power is supplied to operate all systems from
the tractor battery.
It is important to note that each module (cab unit, trailer unit,
radar, boom section, spray fluid containers, nozzles, etc.) are
interconnected by relatively simple and reliable connectors. Extra
boom units or nozzles can be added at any time. And the electronics
can be designed (e.g. programmed) to automatically adjust to such
additional components. These interconnections are illustrated in
FIG. 6A.
The operator's panel is shown at FIG. 10 and is explained in more
detail subsequently. However, an intital overview of the system
operation is most easily understood by reference to operator
console or "Cab Unit", shown in FIG. 10. There are three main
sections: (1) routine controls on the left hand side; (2)
monitoring displays in the middle and on the right hand side; and
(3) controls to set spraying conditions on right hand side.
On the left hand side the operator's routine controls are to start
or prime the system, spray, pause while turning the tractor and to
flush after completing the field. The monitoring section indicates
the allowed speed range, volume of chemical remaining and any fault
or alarm conditions. The right hand section for selection of spray
conditions is used to override the recommended applications rate,
to select mixes of different chemicals and to record the
separations between nozzles (which are operator set as desired by
moving and securing individual nozzles to a slide bar on each boom
section). A switch selection of the number of connected nozzles may
also be provided if provisions are not otherwise made to
automatically count the number of spray heads connected into the
system at any given time. However, it is anticipated that a given
farmer will rarely change these settings. In this case this system
operates fully automatically. If the required chemical containers
are connected, pressing "prime" and then "spray" controls will
automatically apply the chemical at the recommended application
rate.
In operation the tractor driver switches on the system and selects
the desired chemical (e.g. from container 209) using controls 224.
Microprocessor 207 then instructs microprocessor 206 to open the
appropriate solenoid valve 221, and to activate the appropriate
pump 228 at a basic pumping rate determined by information
pre-coded on memory chip 214 associated with container 209. The
basic pumping rate is however modified according to data received
from radar unit 203. This unit measures tractor forward speed, and
communicates it to microprocessor 206 via microprocessor 207.
Microprocessor 206 computes the pumping rates necessary to keep the
spray delivery rate per unit area constant at the desired value
with changes in tractor speed, and instructs the appropriate pump
228. Microprocessor 206 also activates electrostatic spray nozzles
213 at a basic voltage determined by information pre-coded on the
corresponding memory chip 214, and varies this voltage as the
pumping rate is changed (the higher the pumping rate the higher the
voltage) so as to maintain spray electric charge and droplet size
within desired limits.
While it might be thought better to use only one CPU and thus
simplify and reduce the cost of the required electronic circuits,
the present split CPU arrangement has been discovered to be more
advantageous for an agricultural spray apparatus of this type. This
is so because for example, much more complex communication circuits
would otherwise be required between the cab and the trailer units.
In this adverse environment, such complex data communication
circuits are not only more expensive, they are probably less
realiable. Accordingly, it is preferred to provide CPU facilities
at both the cab and trailer sites with any required
intercommunications being via simple data transmission lines. Thus
only a simple two conductor connection, for example, may be
required between the cab unit and the trailer unit. In a modular
agricultural spraying system of this type, the cost of
interconnecting the modules is considered important. The chosen
distributed logic architecture of the electronics minimizes such
interconnection costs. The containers, boom sections, and nozzles
communicate with the trailer console which, in turn, communicates
to the main processor (in the cab) via a simple two wire serial
data link.
The system can be divided into the operator functions that take
place in vehicle cab and the functions related to controlling,
pumping and sensing the spray liquids from container to nozzle.
These two functions are physically separated by some meters and the
design aim is to minimize the wiring between them and to provide
easy installation and security of operation. Using one central
computer controlling all functions would require 20 to 30 separate
connections between cab ans spray system. In order to reduce this,
additional electronics are required at each location to "serialize"
the data. With low cost processing power available (e.g. in the
form of 8-bit microcomputers), it has been determined that
distributed microprocessor architecture is the most cost effective
and reliable way to achieve a spray system of this type. A
microprocessor in the cab unit and in the spray system reduces the
connectors to only two data wires between these locations.
A single microprocessor in either the cab or trailer unit may
typically require eleven integrated circuit "chips" to carry out
all functions. These interface with conventional analog buffers and
other I/O circuits to drive and sense the spray system elements and
display. Dividing the functions between two processors as taught
here may, for example, require seven integrated circuits with the
spray hardware, and six integrated circuits with the display in the
cab--an increase of two integrated circuit chips. This is an
increase of about 5% in the cost of the computing circuits against
a saving in cable from 30 to 2 conductors, over up to 4 meters. The
saving in cable, connectors, and installation dramatically outweigh
the increase in the cost of electronics, especially as the
environmental requirements in the adverse environment of toxic
chemicals, heat, dust, sunlight, etc. may make expensive cable
necessary.
The distributed logic architecture is shown generally at FIG. 7 and
in more detail at FIG. 7A. In FIG. 7A, it will be seen that the
electronic hardware architecture at each individual site (i.e. the
cab unit and the trailer unit) is basically a conventional
bus-connected microprocessor electronic data processing system. An
important novel feature of the overall architecture is the
distribution of logic control circuitry between the cab unit and
the trailer unit so as to provide a more reliable and economic
agricultural sprayer.
The various individual components shown in FIG. 7A may be purchased
commercially and may typically be:
TABLE 1 ______________________________________ Integrated circuit
type ______________________________________ Microprocessor 6802
Address Decoder 741LS138 ROM" 2716 Parallel 6821 I/O Ports Serial
I/O Ports 6551 Transistor BD437 buffers Stepper Motor 2N3055
Interface Timer PA6840 Opto Isolators 2N33 RADAR unit Plesey POME
20/Dev. ______________________________________
Suitable programs for the microprocessors of FIG. 7A are described
below by an operational description of the intended system
functions and by program flow charts shown at FIGS. 18-21.
The cab unit includes the display and control panel, which is
connected to the processor as multiplexed 10.times.8 array. The
processor implements the operator control sequence and drives the
display accordingly. It receives information from the trailer unit
about liquid levels, the presence of liquid in the pipes, and the
condition of nozzles. It transmits operator commands to the spray
trailer unit to control solenoid valves and pumps. It informs the
trailer unit of the output of the radar speed measurement system,
with which it communicates. The display is shown in FIG. 10.
The trailer unit processor monitors and overwrites the information
in the container coding devices. It adjusts the rates of the
delivery pump with reference to the set flow rate and information
received from the cab unit, (i.e. required delivery rates, nozzle
spacing, chemicals selected and vehicle speed). It communicates
with and controls the nozzles on the spray boom, monitoring their
condition and number, and controlling the high voltage. It
communicates their status to the cab unit as described above. The
processor interfaces with the trailer unit hardware via an analog
control board as should be appreciated.
Various elements of the system will now be described in more
detail.
FIG. 8 shows the fluid circuit 212 in more detail. Feeding it are
containers 209, 210 of formulated chemical and another container
211 of flushing diluent for cleaning the circuit after use. Each
container has a cap 229 containing a memory circuit 214 pre-coded
with information relating to the container contents, and including
mated mounting apparatus 230 for demountably attaching the
container to the system. The container and mount 230 are described
in more detail in connection with FIG. 9 below. Liquid can pass
from each container to infrared liquid detection deices 216 (which
report to trailer microprocessor 206 the presence or absence of
liquid) and thence to 2-position 3-way solenoid valves 221. These
valves, in the "on" position, connect the adjacent container into
fluid circuit 212; in the "off" position, they block passage of
fluid into circuit 212 and thus bypass the associated
container.
Hence the selected fluid passes via pumps 228 to junction box 231.
Pumps 228 are preferably metering gear pumps provided with stepper
motors, and are controlled by microprocessor 206, as are also
solenoid valves 221. Alternatively, a non-metering pump may be used
in conjunction with a conventional flow metering arrangement.
Beyond junction box 231 is a further liquid detection device 217
for reporting the presence or absence of liquid to microprocessor
206. From here, the liquid circuit 212 leads to boom 205 and
terminates in nozzles or spray heads 213. At the opposite end of
circuit 212 is an air pump 232, also controlled by trailer
microprocessor 206, which may be used to clear circuit 212 of
liquid.
Operation of the fluid circuit 212 is as follows. The tractor
driver selects one chemical to be sprayed (say the chemical in
container 209), using controls 224, (alternatively he may select
both chemicals for spraying together; if they are compatible) and
activates the "Prime" control. Microprocessor 206 is then
instructed to move solenoid valve 221 to the "on" position, so that
liquid enters the circuit 212 from container 209 as far as the
corresponding pump 228. Microprocessor 206 also activates the pump
228 to pass liquid through the circuit 212 to liquid detector 217.
This reports the presence of liquid to microprocessor 206 which in
turn communicates with microprocessor 207 to cause the display 225
to indicate that the system is ready to spray, and turns off the
pump 228. The operator now activates a "Spray" control on the cab
unit 202 and drives the tractor over the terrain it is desired to
spray. The radar unit 203 senses the tractors forward speed and, as
soon as this is within operation limits, the microprocessor 206 is
instructed to start metering pump 228 so as to supply liquid to the
boom 205 and nozzles 213.
The compatibility of one chemical with another is a matter for a
decision by chemical experts. Information relating to the identity
of the chemical in the container is stored in a portion of the
memory chip 214. If two containers with different chemicals are
connected into the same system then each container will have the
identity of its own chemical. Incompatibility can be accomplished
in two ways.
Firstly each container memory can also contain a list of
incompatible chemicals which can be compared in the microprocessor
by a correlation procedure with the identity of the other chemicals
and if a match is found the system can be shut down. If the
identity of each chemical is stored as a digital number in a known
series of digital numbers then the cross correlation of
incompatible chemicals is relatively simple.
Secondly the microprocessor could itself contain a list of
incompatible chemicals and could interrogate the containers
connected to the system and decide on the compatiblity of their
contents.
The container memory 214 can also contain in a preferred embodiment
a security code which can be used on initialisation of the system
to determine that a correct container has been fitted. If the
container has an unaceptable security code then this may mean that
the chemical coding has been changed e.g that the container is too
old kor that the chemical is now not acceptable. Thus this security
code can be used to prevent usuage of chemicals without changing
the identity code and also to prevent unauthorised containers being
successfully connected to the system.
During spraying, the microprocessor 206 senses the volume of liquid
withdrawn from container 209 (by integrating the pumping rate over
time). Each time 10% of the liquid capacity of container 209 has
been withdrawn, the microprocessor 206 revises the contents of
memory circuit 214 on container 209, making a permanent entry (e.g.
by severing fusable links in a PROM circuit) in this memory. If the
volume of liquid withdrawn from container 209 as permanently
recorded in memory 214 should reach 120% of the nominal container
capacity, microprocessor 206 is programmed so as not to permit any
further pumping--this prevents container 209 being refilled except
under factory conditions. Also, when container 209 empties in the
course of operation, so that its adjacent liquid sensor 216 begins
to register absence of liquid, the microprocessor 206 will make a
permanent entry (e.g. by severing fusible links in a PROM circuit)
in the memory 214, to prevent further pumping, thus effecting the
same purpose.
After spraying the desired target, the driver re-activates the
"Spray" control, which causes spraying to cease. He may then clean
the system out with flushing liquid. Activating the "Flush" control
will cause microprocessor 206 to control the valve associated with
container 209 to close and the valve associated with 211 to open.
Pump 228 is again activated, and flushing liquid passes for a
preset time through the previously used portion of circuit 212 and
out through nozzles 213. Finally, microprocessor 206 will close
valve 221 by container 211, and activate air pump 232 to pass air
through circuit 212 until it is clear of liquid.
The container coding device 214 is preferably a custom-designed
fusible link PROM. For example, a standard 32.times.8 Bipolar
Fusible Link PROM may be adapted to this use by incorporating
conventional I/O microcircuits therewith to form a single special
purpose or customized integrated circuit especially adapted for
this use. It is preferably physically integrated into the cap of
every legitmate fluid container and is electrically connected to
the trailer unit electronics upon attaching the container for use.
The PROM is pre-coded with information pertaining to the chemical
during the filling operation. The PROM contents are subsequently
irreversibly updated during usage with data representing the
remaining volume of liquid. A check should be made when
interrogating the container during usage to insure that all
pre-coded information is of a correct and legitimate format. Such a
format check may be re-inforced, if desired, by a coded "handshake"
exchange of communication between the container and the spray
system before usage is permitted. Typical memory allocation for a
given container may be:
TABLE II ______________________________________ Read Only a.
Handshake security code 8 bits b. Acceptable flow rates, per unit
12 bits area, minimum, maximum, optimum c. High voltage setting 4
bits d. Container size 8 bits e. Chemical type 16 bits f.
Formulation data 8 bits Read/Write a. Liquid quantity 13 bits
______________________________________
The read/write data in container coding device 214 indicates the
quantity of liquid left in or so far removed from the container.
This is preferably updated in a non-reversible manner. A fusible
link PROM is one possible device that may be used. In one possible
coding scheme, one bit per increment of quantity stored is used. If
10% increments are used and up to 120% of the potentially available
volume is permitted to be used before disabling the sprayer (thus
allowing for a margin of error), it follows that 13 bits would be
required.
The data required for container coding may, for example, be held in
an 80 bit store implemented as a 10 by 8 bit array. It may be
conveniently read as 10 serial words of 8 bits each over a
synchronous or an asynchronous serial link. Peferably a custom CMOS
device could be used (including any required I/O interface) for all
containers and chemicals. This custom device would have the proper
Read Only information inserted on the container filling line. The
"Read/Write" portion of the PROM would be left unwritten so as to
indicate a full container. Then, during use, the spray system will
write data (by electrically breaking fusible links) as appropriate
to represent metered liquid usage. A handheld interrogation unit
may be designed if desired to permit a user to read the entire
contents of the container coding device.
The container 209 and its connector 230 are shown in more detail in
FIG. 9. The container is, in some respects, the cornerstone of the
entire spray system. It protects against unauthorized filling; it
provides automatic control over critical spray parameters; it
provides a closed fluid system which requires no mixing by the
farmer; and it is consequently safe to operate. In fact, the
container itself becomes a peripheral part of the data processing
portion of the spray system.
The container 209 is shown inverted, having a cap 229 which is of a
resilient plastic material which can sealingly grip the edge 223 of
the container opening. The cap is fixed with a supply outlet 234
and a vent inlet 235. Inside the supply outlet 234 is a shaped
sealed ring 236, formed of rubber or like material. A sealing plate
237 is urged against sealing ring 236 by compression spring 239 the
other end of which abuts a circumferential flange 240 within the
upper end of outlet 234. Secured inside the vent inlet 235 and
extending toward the upper end of the container 209 is an elongate
duct 241, at the inner end of which is a spring-loaded ball valve
242, sealing the duct 241 against leakage of fluid form within
container 209 but permitting air to enter container 209 when the
pressure differential is sufficient ot overcome the spring-loading
of ball valve 242. The cap 229 also carries a pre-coded
microcircuit chip 214 mounted to communicate via external
conductive socket connections 243. The outer edge of cap 229
carries a thread 247, and for transport and storage carries a
protective threaded cap lid (not shown).
The container 209 is mounted on the system via the connector 230,
shown immediately below it in FIG. 9. This comprises a cover member
244 formed with a flanged edge 245 supporting a freely rotatable
threaded collar 246 which can engage with thread 247 to hold cover
member 244 and cap 229 tightly together. Cover member 244 is formed
with a projecting supply pipe 248 to mate with outlet 234, a
projecting vent pipe 249 to mate with vent outlet 235 and female
electrical contacts 251 to mate with male sockets 243. Connections
215 from contacts 251 lead to microprocessor 206; supply pipe 248
leads to sensor 216 and thence to liquid circuit 212 while vent
pipe 249 leads out into the atmosphere. Pipe 248 projects to a
height sufficient so that, sealing plate 237 is lifted off sealing
ring 236 so liquid can flow out around the edges of plate 237
(which for this purpose are preferably partly cut away) into pipe
248.
Each nozzle preferably also includes an integrated circuit I/O
device to perform the following I/O operations at each nozzle
site:
(a) Communication with the Trailer Unit on a serial line in a
"daisy chain" configuration with the other nozzle devices. This
allows the Trailer Unit to automatically count the number of
nozzles or spray heads attached to it and to control and monitor
them over a very simple connection.
(b) Control of high voltage by driving a high voltage transformer
and diode/capacitor stack to maintain droplet size with flow
variation.
(c) Monitoring of spray condition and detection of faults.
(d) Drive to a solenoid valve for boom section isolation.
A top view of the cab unit 202 is shown in FIG. 10. This connects
to the radar unit 203 via demountable plug and socket connection
252 and to the microprocessor 206 into the trailer unit 204 via
demountable plug and socket connection 253. Unit 202 incorporates
microprocessor 207 (not visible in FIG. 10) which operates the
displays 225 shown on the panel 223. It is actuated by input from
the radar unit 203, the panel controls 224 and input from the
microprocessor 206 in the trailer unit via connection 253. Of
course microprocessor 207 also transmits control information to
microprocessor 206 via connection 253.
The displays 225 are light-emitting diode units (LEDs), coloured
distinctively either yellow or red, and operable by microprocessor
207 to give either a steady light or to flash. Each LED 225 is
provided with an adjacent label to show the tractor operator its
function.
The spray controls are grouped on the left of panel 223. They
comprise three actuating buttons 255, 256, 257 labelled
respectively "Spray/Pause", "Prime" and "Flush". Button 255 is
associated with a yellow LED 258 labelled "Pause/Ready"; button 257
is also connected with LED 260 as well as with a red LED 261
labelled "Required". Four yellow LEDs 262 grouped together and
labelled "Spraying" complete the spraying controls/display
complex.
At top centre of the panel 223, the speed of the tractor is shown
by a horizontal row 263 of 8 yellow LEDs 264, beginning and ending
with red LEDs 265, 266. This row is labelled "Speed" below and
"Range" above. Each yellow LED 264 is labelled with the speed it
represents (in miles per hour from 2 to 9). Red LEDs 265 and 266
are labelled "Low" and "High" respectively
At centre of the panel below the "Speed" display is the "Level"
display comprising two left and right parallel verical columns 267
and 268 each of 10 yellow LEDs 269, each terminating in a red LED
270. Above each column 267, 268 and slightly displaced from it is a
red LED 270. LEDs 271 are labelled "Check container fitting". The
left array 267 is labelled "Spray" while the right is labelled
"Flush". The arrays are graduated from "Full" at the top, through
"Half" to "low" opposite the lowest yellow LEDs 269 and the red
LEDs 271 are labelled "Empty".
Below the "Level" display, at lower centre of the panel 223 are
four red LEDs 272 grouped together and labelled "Alarm".
At top right of the panel 223, the "Nozzle Spacing" control
comprises a knob 273 having a pointer 274 which may be set by
manual rotation to any of seven positions labelled "A" through
"G".
Below the "Nozzle Spacing" control at right centre of pannel 223,
the "Port" control/display complex comprises a 3.times.5 array of
LEDs, in five vertical columns 274 through 278. LEDs in centre
column 276 are unlabelled (they relate to the flushing liquid)
while columns 274, 275, 277 and 27 are numbered 1 through 4. The
top row of LEDs in the array is labelled "Selected"; the second row
"Container"; the third "Display". A control knob 279 may be set by
manual rotation to indicate any one of the 4 columns 274 etc. Below
knob 279 is a depressible button control 280 labelled "Select". A
single red LED 281 to the left of button 280, labelled "Invalid
mix" completes the "Port" control display complex.
At lower right of panel 223 is the "Spray Rate" control/display
complex. This comprises a row 281 of seven yellow LEDs, forming a
scale labelled from left to right, with application rates they
represent (e.g. 7, 10, 15, 20, 30, 40, 50 fluid ounces per acre).
Beneath row 281 are a pair of depressible button controls 282, 283
each labelled with an arrow pointing up or down scale.
Finally, along the lower edge of panel 223 is the "Boom Control"
control/display complex. This comprises a spaced linear array of
five depressible button controls 284 each associated with a yellow
LED 285. The outer buttons 284 are labelled "Left" and "Right"
appropriately, and the centre button 284 is labelled "Centre".
A master switch 286 provides power to the display and controls.
In operating, the tractor driver first switches on the master
switch 286. This activates the displays 225. The actual state of
the displays 225 will now depend on the state of the system. In
this description it will be assumed that all switches are off. The
"Level" display will then show no light in column 267, but will
indicate the level of flushant liquid in container 211 by the
number of LEDs 269 which are lit. Alternatively if container 211 is
missing or not properly fitted, the corresponding red LED 271 is
lit. If all is in order, the driver sets the nozzle spacing as
required by rotating knob 273 and selects the required boom
sections by depressing one or more of buttons 284. After depressing
each button 284 the adjacent yellow LED 285 comes on to confirm the
boom section is selected. To cancel selection the button 284 is
depressed again and the LED 285 goes out. Now a spray container
(e.g. 209) is selected by rotating the control knob 279 to the
appropriate control column (say 274) and depressing "Select" button
280. In column 274 all three LEDs are lit; the top LED indicating
that container 209 has been selected; the centre LED that it is
connected to the system; and the bottom LED that it is registering
on the spray display (column 267). column 267 now registers the
liquid level in container 209. If (alternatively) the container 209
is badly fitting or absent, the red LED 271 above column 267 will
light and the lower LED in column 274 will flash. If
(alternatively) container 209 is empty, the centre LED in column
274 will flash, and the appropriate red LED 270 in the "Level"
display will light. If the container 209 is nearly empty, the top
LED in column 274 will flash, as well as a low level being shown in
the "Level" display.
If the operator wishes to check the level in a second container
(say 210) he may turn knob 279 so that it it indicates the
appropriate column (say 275). The bottom LED in column 275 then
lights, while the bottom LED in column 274 goes out (the other two
LEDs in 274 however remaining lit). The display in column 267 now
changes to show the level in container 210.
If the operator wishes to spray a mixture of chemicals from
containers 209 and 210 he may now press button 280 again. If the
chemicals in containers 209 and 210 are compatible (so that they
may safely be sprayed together without damage to crops or spraying
apparatus), the top LED in column 275 will light; if not, it will
remain unlit and the "Invalid Mix" LED 281 will light.
Assume the operator wishes to spray from container 209 only, so
that all three LEDs in column 274 are on, and no other "Selected"
LEDs are on in column 274-7. Three LEDs will now be on in row 281
of the "Spray Rate" display. Two steady lights indicate the maximum
and minimum permissible spray rate for the chemical selected. A
third flashing light shows the spray rate currently selected. The
operator adjusts this to a desired value within the maximum and
minimum range by pushing buttons 282 or 283 to increase or decrease
the selected spray rate stepwise as may be required. Chemical and
spray rate have now been selected.
The operator next turns his attention to the spray control on the
left of panel 223. If the liquid circuit 232 is empty, the yellow
LED 259 will be lit, indicating "Prime Required". The operator
therefore presses button 256. As a result, LED 259 goes out and LED
260 lights, indicating "Prime in Progress". Microprocessor 206
activates pump 228 to cause liquid to flow from container 209 into
circuit 232 down as far as nozzles 213. When this is complete,
microprocessor 207 turns off LED 260 and lights LED 258 indicating
"Pause/Ready". At this stage, two LEDs 264 are lit in row 263 of
the "Speed" display. These indicate minimum and maximum forward
speeds between which the system can apply the selected chemical at
the selected rate.
As the operator drives the tractor over the crop to be sprayed, the
actual speed is indicated by a LED 264 flashing in row 263. When
the speed is within range, and the tractor is on the right path,
the operator presses "Spray" button 255. Then LED 258 goes out and
the four LEDs 262 light, indicating "Spraying" while voltage and
spray liquid pass to the nozzle 213 and spraying begins. To stop
spraying for short periods (e.g. to turn the tractor) the operator
presses button 255 again whereupon LEDs 262 go off and LED 258
comes on. Spraying is then restarted by a futher touch on button
255.
During spraying, microprocessors 206 and 207 continously monitor
tractor speed and change the speed of pump 228 to maintain a
constant application rate of chemical per unit area. At the same
time they adjust the voltage supplied to nozzles 213 as flow rate
changes so as to maintain particle size and charge of the spray
droplets within appropriate limits. If the tractor speed is not
kept within the necessary limits shown in row 263, one of red LEDs
265, 266 will come on, indicating "high" or "Low" as appropriate.
If the tractor speed remains outside range for longer than a short
preset time, spraying ceases, LEDs 262 are extinguished and red
"Alarm" LEDs 272 come on, flashing.
When the desired spraying is complete, spraying is stopped by
pressing button 255 to show "Pause/Ready" by LED 258; after a
preset time LED 258 extinguishes and LED 261 lights indicating
"Flush Required". The operator presses button 257 initiating the
flush sequence while LED 261 goes out and LED 260 lights,
indicating "Flush in Progress". Microprocessor 206 closes valve 221
to isolate container 209 from circuit 212 and opens valve 221 to
connect flush container 211 into circuit 212. Pump 228 is
activated, draining flushant liquid around circuit 212 and out
through nozzles 213. After a suitable volume of flushant has been
introduced into the system, valve 212 is closed and air pump 232 is
activated to empty circuit 212 of flushing liquid. When liquid
detector 217 reports no liquid, after a short preset time to allow
liquid to clear the nozzles, pumps 228 and 232 are switched off,
LED 260 goes out and LED 259 comes on, indicating "Prime Required".
Master switch 286 may now be switched off, to close down the
system.
Elements in the spray circuit 212 such as pumps, valves, sensors
etc. are conveniently connected together by dual purpose fluid and
electrical connectors. A suitable type of connector is shown in
FIGS. 11 and 12. The connector arrangement comprises two bodies 287
and 288 which are adapted to abut along their faces 289 and 290 and
be secured together. The first body 287 is provided with a hole 291
which extends through the body 287 and the end of which is a
projecting duct portion 292 from the face 289. The other end is
provided with a stub pipe 293 for receiving a flexible liquid hose
(not shown). Four smaller holes 294 are also provided, in each of
which is fitted an elongate electrically conductive strip 295. One
end 296 of each strip projects from the body 287 so as to be
readily connectable to an insulated electrical conductor (not
shown) while the other end 297 projects from the face 289.
The second body 288 is also provided with a hole 297 which extends
through the body 288 and is provided with a stub pip 298 for a
flexible liquid hose (not shown). Four further holes 299 are
provided in each of which is located an electrical socket 300
having an elongate strip portion 301 extending out of the body 288
for connection to an insulated electrical conductor (not shown).
The hole 297 is adapted to receive the duct portion 292 and a
sealing ring 302 is located in hole 297 so as to make a sealed
joint with duct portion 292. Similarly the sockets 300 are adapted
to receive the ends 297 of the strips 295 and the two bodies 287,
288 can be pushed together until faces 289, 290 abut.
It is often convenient to form the insulated conductor and the
flexible liquid hose emerging from body 287 (or from body 288)
integrally with one another. It may also be convenient, for
connecting together certain parts of the system, to include ball
valves in the liquid connector orifices to prevent liquid leakage
on disconnection.
A double ball valve which serves to shut both orifices on
disconnection is shown in FIG. 13. This comprises two bodies 303,
304 each having a through duct 305, 306 respectively and each
having a stub pipe 307, 308 for connection to a flexible hose (not
shown). In the duct 305 is located a ball 309 which is urged
towards a conical seal 310 by a spring 311. Between seat 310 and
the right end of the duct 305, the diameter of duct 305 is reduced,
housing loosely a moveable valve actuator 313, movement of which is
restricted by two shoulders 314, 415 formed inside duct 305.
Extending from each end of valve actuator 313 are stems 316,
317.
The end of duct 305 extends through a cylindrical projecting
portion, thereby sealing duct 305. The valve actuator 313 is at the
same time urged by ball 309 toward shoulder 315. The body 304 is
also provided with a ball 318 urged toward a conical seat 319 by a
spring 320, the left end of duct 306 having a diameter which will
accept the projecting portion of body 303. An annular seal 323 is
located inside the left end of duct 306. When bodies 303, 304 are
not abutting, the ball 318 seating on seat 319 seals duct 306
against leakage. When the two bodies 303, 304 are pushed together,
however, the projecting portion 322 enters end 324 of duct 306 and
stem 317 contacts ball 318. Spring 320 is stiffer than spring 311
and valve actuator 313 is accordingly moved within duct 305 until
stem 316 contacts ball 309 and displaces it from seat 310. After
further movement the actuator 313 is stopped by shoulder 314, and
further approach of bodies 303, 304 causes stem 317 to move ball
318 off seat 319. In consequence, when bodies 303, 304 are fully
mated, both ball valves are open. On separating, the action of
springs 311, 320 seals both valves again to prevent leakage.
In certain parts of the system, in particular the array of nozzles
213 mounted on boom 205, it may be desirable to attach or remove
devices (in particular, nozzles) in series without breaking the
electrical circuit. For example, if the preferred serial "daisy
chain" data communication link is used for the nozzles, the series
"daisy chain" should remain unbroken even if a given nozzle is
disconnected or a given connection socket is never used. FIGS.
14-16 illustrate an electrical connector which carries out this
function automatically. The connector comprises first and second
bodies 325, 326 which may be joined so that their respective faces
327, 328 abut. Extending through the body 325 are four electrical
conductors 329 with first ends terminating at face 327 in the form
of sockets. The second ends of the conductors 329 (not shown) are
attached to separate electrical conductors. Mounted in a recess 330
in body 325 is an electrically conductive hairspring 331 having
extended legs 332, 333 which are urged into contact with two of the
conductors 329. A moveable plate 334 also located in recess 330 is
provided with a lug 335 which engages leg 333 so that plate 334 is
urged therby into the position shown in FIG. 14. A hole 336 is
formed through plate 334 and a similar hole 337 in body 325, but
the two holes 336, 337 are slightly out of alignment when plate 334
is in the position shown in FIG. 14.
Body 326 is similarly provided with four conductors 338 extending
therethrough to project from face 328 being disposed so as to mate
with the sockets of conductors 329 in face 327. A tapered
projection 339 also projects from face 328. When the two bodies
325, 326 are brought together so that faces 327, 328 abut, the
projecting conductors 339 enter the sockets of conductors 329 and
the tapered projection 339 enters hole 337, and also hole 336 in
plate 334. This brings holes 337 and 336 into alignment, sliding
plate 334 into the position shown in FIG. 16. In this position leg
335 has pulled leg 333 out of contact with conductor 329. When the
two bodies are separated, leg 333 returns to the position abutting
conductor 339 that is shown in FIG. 14. It will be seen that when
the connector is incorporated in an electrical circuit, the leads
attached to conductors 329 will be electrically bridged when the
bodies 325, 326 are not joined, while joining the bodies breaks the
bridge.
For many purposes relating to the invention it may be convenient to
use connections using more than one, or all, of the features of the
connections shown in FIG. 11-16.
The design of a nozzle 213 as used in this embodiment of the
invention is shown in more detail in FIG. 17. The nozzle assembly
is in two parts: an upper low-voltage housing 340 and lower
high-voltage nozzle-carrier 341. Housing 340 comprises an
electrohydraulic connector 400 of the type illustrated in FIGS.
11-16, for connection of the nozzle 313 into liquid circuit 232 and
for providing electrical connections with microprocessor 207, a low
voltage power source (the tractor battery) and with earth. The
connector 300 is joined flexibly to the main body 342 of the low
voltage housing 340. This carries an integrated circuit 343 which
serves as interface with microprocessor 206 and a spring-loaded
ball valve 344 seals a central liquid delivery orifice. The
external cylindrical surface of body 342 is threaded to receive the
upwardly extending threaded skirt 401 of nozzle carrier 341. This
comprises a central delivery tube 346 which mates sealingly with
the central delivery orifice of housing 342, having an upwardly
extending central finger 347 for opening ball valve 344.
In the lower part of tube 346 is positioned a conductive cylinder
348 to form a nozzle 351 having an annular spray orifice 349.
Spaced from the orifice 349 is a dependent insulating skirt 350
which protects the nozzle 351 from accidental contacts. Supported
within skirt 350 coaxial with tube 346 and cylinder 348 above the
level of orifice 349 is a metal annulus 352 coaxial with tube 346
and cylinder 348. Annulus 352 serves as a field-intensifying
electrode, and is connected to earth via contact 353 in carrier 341
which abuts contact 354 in housing 340.
Around the upper part of tube 346 is disposed a conventional
toroidal high voltage generator 355 of the type using a diode split
transformer. The output voltage of generator 355 is fed to cylinder
348 via a suitable conductor. The output voltage of generator 355
is controlled by the input signal fed to it from microcircuit chip
343 via contacts 357 on carrier 341 and contacts 358 on housing
340. Means not shown adjustably secure the housing 340 firmly to a
mounting bar on boom 203 (see FIGS. 6, 7) at any desired spacing.
It is usually necessary that the nozzle 213 should be in a fixed
orientation at a fixed distance above the crop.
If nozzle 213 fails in use it may readily be replaced--either as a
whole, or by unscrewing (the threaded connections may be of a
"quick connect" variety requiring less than a full turn to effect
connection or disconnection) nozzle-carrier 341. In this embodiment
the nozzle's flow capacity can be increased or reduced merely by
changing unit 341 for another unit having a larger or smaller
orifice 349. Other embodiments may readily be visualized in which
flow capacity may be adjusted by relatively rotatable splined
cylinders abutting end-to-end. Such a valve could be set either
manually or automatically by operation of microprocessor 206.
The radar unit (see FIG. 6) comprises conventional means for
emitting a microwave beam of known frequency forwardly and
downwardly in the direction of motion of the tractor, with means
for detecting that part of the beam reflected back to the unit and
comparing its frequency with that of the emitted beam. The
frequency difference is a measure of the tractor speed (Doppler
effect) and the information thus obtained is fed to microprocessor
207.
Microprocessors 206, 207 (see FIG. 7) are conveniently of the 6802
type. This is a standard 8-bit processor, of fully adequate
capacity, which interfaces with standard memory products and a wide
variety of peripheral circuits. Each microprocessor 206, 207 has a
computer board with central processing unit, read only memory and 3
or 4 peripheral circuits. The use of two linked microprocessors in
the cab unit 202 and trailer unit 204 gives a system with much less
complicated and hence cheaper interconnections between the cab and
trailer units.
The system may comprise customized integrated circuits of two
kinds; those (214) in the containers 209 etc. and those (343) in
the nozzles 213. The former is a memory circuit (possibly including
I/O interface circuits) pre-coded with information (range of
application rates, voltage, compatibility with other chemicals,
etc.) relating to the chemical when the container 209 is filled at
the factory. It may also include a security code. Chip 343 in the
nozzle unit preferably includes an I/O device and communicates with
microprocessor 206 in trailer unit 204, which is thereby enabled to
count the number of nozzles 213 attached for spraying. Chip 343
preferably also controls the nozzle voltage via the generator 355.
And, it could also be used to monitor the manner in which th
enozzle sprays (by means, for example, of devices such as those
shown in FIGS. 4 and 5), to drive a solenoid valve to isolate parts
of boom 205 or to change effective orifice sizes, etc. Chip 214 may
be designed, for example, to store about 80 bits of information as
tabulated previously.
This exemplary spray system incorporates these sensors
(a) speed sensor;
(b) liquid presence sensor;
(c) spray presence sensor (and/or nozzle failure sensor); and
(d) flowmeter (not required for self metering gear pump).
Compensation for tractor speed variations is preferably made
dependent upon the output of a radar unit after studying the nature
of the errors in radar and other systems. Conventional speed
monitors using a wheel, while capable of the required resoluiton,
have fixed offset errors due to slipping or diameter errors. The
operator is required to enter the actual circumference and an error
may also occur here. In contrast the radar requires no operator
setting and once set correctly on the tractor gives true speed
indication. A further consideration is that future tractors are
likely to have radars fitted by the manufacturers as standard. The
cost of a wheel unit and an OEM radar unit are comparable making
radar the preferable choice for this sensor requirement.
The liquid presence sensor has two functions in the system. It is
used to check the presence of liquid during the priming cycle and
to give a positive indication that a chemical container has
emptied. In neither case is a quantitive signal required. A
suitable electro-optic sensor is presently preferred. That is, a
sensor where indicent light (for example, conducted in a light
fiber) is passed through the liquid medium and the reflected or
residual transmitted light is then sensed (again, for example, via
a light conducting fibre) to obtain an indication of fluid
presence.
Nozzle failure may be detected and indicated to the operator as
explained with respect of FIGS. 4 and 5. However a suitable
electro-optic sensor similar to the liquid presence sensor may also
be used. The design of the nozzle allows for the rapid replacement
of the lower section or complete nozzle, (see FIG. 17), and for
incorporation of a fibre optic spray presence sensor.
The nozzle control electronics transmits a failure indication to
the trailer unit which is then sent on to the main controller. An
additional red light may be employed to indicate that a nozzle
failure has occurred. It would be possible to indicate which nozzle
by an additional LED array but, to maintain the modular concept of
the system, a single signal light on the display is to be preferred
with an LED on the actual nozzle housing indicating which nozzle
has failed. The user should carry a spare unit and could replace
the unit in a few seconds.
To maintain control over the true liquid application rate per unit
area the volume of liquid delivered to the booms must be precisely
known. For a gear pump with a high volumetric efficiency the
delivered volume is given by the angular rotations of the pump
which in turn is given by the number of steps of the stepper motor.
This is referred to as self metering mode. If higher volumetric
efficiency is desired, an alternative pump and motor combination
may be used with an additional flow meter. High resolution is
desirable as this decreases the time response of the system and
increases spraying accuracy. "Nozzle" is generally used in
describing the embodiment of FIGS. 7 et. seg. to mean a complete
high voltage generator and nozzle assembly. The use of a custom I/O
integrated circuit to act as a communication interface to the main
control microprocessor was described earlier. The same integrated
circuit would generate the low voltage control signals for the high
voltage generator. The design concept for nozzle assembly is shown
to FIG. 17. Several important features of the design are as
follows:
(a) two part construction;
(b) flexible connection to boom unit using basic electro-hydraulic
connector;
(c) lower section contains electrostatic nozzle and high voltage
transformer, (removes in quarter turns for quick field
replacement);
(d) upper section contains low voltage electronic and data
interface;
(e) spray sensor e.g. optic link to lower section (not shown);
(f) spray fault signal LED in upper section (and IC transmits fault
signal to display console) (not shown)
(g) permits automatic nozzle count via daisy chain data line (part
of custom IC function which, in effect, instructs arithemetic unit
of trailer unit controller to set appropriate pumping rates);
and
(h) permits automatic signalling of state of viscous restrictor in
fluid path. (Manual or automatic selection of restrictor to suit
application rate range).
A description of the presently preferred embodiment for the
computer programs for microprocessors 206 and 207 follows based on
the flow charts of FIGS. 18-21.
As previously explained, the preferred embodiment utilizes a
microprocessor both in the display unit and in the spray control so
as to reduce the necessary communication wiring between the two
units to only two wires. Preferably, data is passed in this conduit
in serial form, as a repetitive sequence. Conventional input/output
registers and communication circuits are provided for both
receiving and transmitting information in this form at both
units.
The display unit processor periodically scans the status of the
operator-controlled switches (or of the content of data registers
reflecting same) and, if appropriate, formats digital control words
for transmission to the spray control unit. The spray control unit,
in turn, periodically scans the status of its various peripheral
units and formats status-indicating/control words for transmission
to the display unit processor. Such formatted digital communication
words are then periodically and repetitively transmitting between
the units so as to complete the communication link.
Repetitive transmission are preferred so that successive
transmission of the same data may be compared before action is
taken to thus enhance the overall reliability of the system
operation. If a received word is faulty in its parity or
synchronization bits or if two successive transmissions of the same
word do not have the same "address" or if fault with the received
word is in any other way detected, a request for reptition words is
transmitted back to the source of the information which requests a
repeat of the earlier transmitted information. If the communication
process falls out of synchronization, the display unit is caused to
transmit the first word of a new sequence while the spray unit
controller cycles through the bit sequence until a matching
"address" field is discovered. Thereafter, both units commence a
normal communication cycle in synchronization. Since such
communication processes and appparatus are believed conventional in
the art of digital communications, no further detail is believed
necessary.
The main or executive program loop for the spray control unit is
shown in FIG. 18. Here, at "power on" or "reset", initializing
steps 500 and 502 are performed so that all internal data registers
and peripherals associated with the spray control processor are
properly initalized. Thereafter, the fluid detectors are
interrogated at 504, the containers are interrogated and updated at
506 and the boom and nozzle structures are similarly interrogated
at 508. A wait loop at 510 is entered for 10 seconds. If any
interrupts are detected within that 10 second interval, then the
main loop is reentered at task 504 shown in FIG. 18. On the other
hand, if no interrupts are received for a 10 second period, then
this indicates a possible fault condition and, accordingly,
spraying is stopped at task 512 and control is transferred back to
the main loop so that the current status of the spray control unit
and its connected peripherals can be updated so that current
information will be available for eventual transmission to the cab
unit.
The spray control unit is programmed so as to include the two
interrupt routines depicted at FIGS. 19 and 20. The non-maskable
interrupt routine shown in FIG. 19 is entered whenever a
communication word is received from the display unit. After initial
entry of this routine, a test is made at 514 to insure that the
word is of correct format (e.g. parity). If not, task 516 is
entered where the communication circuits are resynchronized before
a normal exit from this routine is made. On the other hand, if the
received word has the correct form, then a check is made at 518 to
see if the addresses of two successive words match. If not, then
this is also an indication that the communication circuits need to
be resynchronized at 516 (which will include an instruction to the
cab unit to repeat the transmission that has been attempted) before
a normal exit from this routine is made.
If the tests at 514 and 518 are both successively passed, then the
received word from the display unit is stored at 520 and a
previously formatted communication word is transmitted back to the
display unit. A test is made at 524 to see if the control word that
has thus successively been received by the spray control unit is
the last intended word in what may be a sequence of such control
words that must be interpreted in context before further action is
taken. If not, a normal exit is made as shown in FIG. 19 so as to
permit the transmission of the next word in the sequence. When the
last word in the sequence has been received as tested at 524, then
the spray control unit calculates the speed/flow and speed/EHT
(extra high tension voltage) if spraying is in progress at 526.
Suitable action is taken based upon these calculations and upon the
received control data at 528. Finally, any internal time-outs are
detected at 530 so that any appropriate housekeeping action
scheduled to occur at such a time-out may be taken before a normal
exit form this routine occurs.
The maskable interrupt routine shown in FIG. 20 is enabled while
spraying and is normally triggered every 3 milliseconds. It is used
for measuring fluid flow and for adjusting the pump speed and high
voltage drive. After initial entry, the flow counter register is
updated at 532 to reflect the current fluid consumption and flow
parameters. A test is made at 534 to see if it is yet time to
adjust the spray parameters (adjustments may only be permitted at
predetermined time intervals so as to prevent undue oscillation).
If not, a fault light is set a 536 if the flow count is detected as
being out of range, otherwise a normal exit is made. On the other
hand, if it is time to adjust the spray parameters, then the pump
speed is adjusted at 538 and the high voltage drive circuits are
adjusted at 540 before a normal exit from this routine. The update
of flow counters at step 532 may typically include the purposeful
fusing of a fusible link in a PROM associated with the container if
it is detected that sufficient fluid has been used.
An exemplary program for the display unit is shown in FIG. 21.
After "power on" or "reset" events, initialization tasks 600, 603
and 604 are performed. Here, any internal registers, peripherals,
etc. are properly initialized and, in the preferred embodiment all
lamps are displayed for 4 seconds at task 604 so that the operator
may make a check on the operability of the lamp display units.
Thereafter, task 606 is entered which causes the transmission of
the word then in the output register to the spray control unit. At
608, a test is made to see if the radar unit is connected. If not,
then the appropriate pattern of display lights is activated at 610
and control is returned to task 612 at the top of FIG. 21 where a
control word is received from the spray unit. A test is made at 614
to see if this is the last word in an intended sequence of such
control words. If not, then another word is transmittted to the
spray control unit at 606. If it is the last word in a sequence,
then it is stored and proper action is taken at task 616.
Thereafter, new data for transmission to the spray control unit is
formatted into the proper output registers at task 618.
If a radar unit is connected to the unit, then after test 608, the
output of the radar is read at task 620 and the average speed is
calculated. A test is then made at 622 to see if the communication
link is working. If it is, all available status information is
displayed at 624, appropriate action is taken on any command
buttons that may be pressed by the operator at 626 and appropriate
action is taken at 628 on any internal time-outs that may have
occurred. Appropriate speed limits are calculated at 630 and, if
desired, control action may be taken if the actual speed of the
vehicle is outside these limits (not shown in FIG. 21). If the
communication link is not working, only the speed is displayed at
task 632 before control is transferred back to the top of FIG. 21
where further attempts may be made to activate the communication
link.
The container may be easily modified to be connected into other
systems and the connections to the memory circuit can be modified
to accept different connectors. The information contained in the
memory may be modified to suit a variety of operating conditions as
required. The memory circuit may be moulded into part of the
container or affixed thereto or it may as shown be placed in a
closure for the container.
* * * * *